Currently there are several different modalities of passive therapy for treatment of human joints. According to one method, one or more electrical stimulator is strapped or otherwise applied to the skin of the patient and electrical impulses are applied at appropriate intensities and frequencies to cause muscle contraction. In accordance with another system, a limb is strapped or otherwise supported on a machine that moves back and forth to flex a joint of the limb, e.g. a knee, elbow or shoulder, while the patient is wholly passive.